Secondly, the ability of the virus to cause congenital abnormalities is probably not limited to the Brazilian offshoot of the Asian lineage of Zika. In an excellent paper that still remains in Biorxiv for now, researchers also used a strain of Zika isolated in Cambodia in 2010, and it performed no differently from the Brazilian strain in infecting placental or neural progenitor cell lines. Representative viruses from the African lineage of Zika have not been similarly tested. Note however the all important clause that effects seen in cell lines and laboratory animals, while important from a scientific perspective, are not proof that the same happens in humans. Microcephaly and other congenital abnormalities had not been associated with Zika in Africa or even on the Micronesian island of Yap in the past, but this can easily be explained by the fact that it would take a very large outbreak for such associations to be noticed. More than 70% of the inhabitants on the island of Yap were infected during the outbreak of 2007, but the population of Yap numbers just about 11,000, and hence it is very unlikely that pregnancy-associated complications would be picked up and attributed to Zika.

But there remain many unknowns about Zika’s effect on the unborn fetus, which well-conducted longitudinal surveys may be able to provide. Zika has been linked to miscarriages, the scale of which is unknown. Other TORCH pathogens are capable of causing developmental delays, hearing loss, etc. even in children born without obvious congenital abnormalities, and further research will be necessary to understand if the same applies to Zika.